Primer for electric and percussion fuses for cartridge ammunition

ABSTRACT

The present disclosure relates to a primer for electric and percussion priming for use in accordance with the spark-gap principle which comprises a metallic capsule provided with a closed bottom, a thrust ring disposed inside of the metallic capsule and completely insulated therefrom by insulating means, and a gap charge provided inside the thrust ring and adjacent the closed bottom of the metallic capsule, the metallic capsule acting as a first lead electrode to the gap charge and the thrust ring acting as a second lead electrode for the gap charge.

Unite States ?atent 1 Gawlick et a1.

[ 51 March 6, 1973 PRIMER FOR ELECTRIC AND PERCUSSION FUSES FOR CARTRIDGE AMMUNITION Inventors: Heinz Gawlick, F urth/Bayern; l-Ielmut Bendler, Erlangen-Spardorf,

both of Germany Assignee: Dynamit Nobel AG, Troisdorf, Germany Filed: July 10, 1970 Appl. No.: 53,774

Foreign Application Priority Data July 11, 1969 Germany ..P 19 35 376.5

US. Cl. ..102/46 Int. Cl. ..F42b 9/08, F42c 1 1/00, F420 19/12 Field of Search 102/46, 28, 70.2 R, 86.5

References Cited UNITED STATES PATENTS 4/1898 Oliver ..102/43 R 1,034,160 7/1912 Starkweather 1 102/46 3,090,310 5/1963 Peet et al 102/46 FOREIGN PATENTS OR APPLICATIONS 1,534,591 6/1968 France ..102/46 805,118 11/1958 Great Britain 102/46 Primary ExaminerRobert F. Stahl Attorney-Craig, Antonelli, Stewart & Hill ABSTRACT 15 Claims, 6 Drawing Figures PATENTEDMR 61m 3,719,148

H01 1 FIG. 2

PRIOR ART PRIMER FOR ELECTRIC AND PERCUSSION FUSES FOR CARTRIDGE AMMUNITION BACKGROUND OF THE INVENTION Primers which are ignited by percussion are convenl0 tional for cartridges. Furthermore, cartridges containing primers which are ignitable by an electric current are also well known. Combined priming systems, which contain an anvil primer to'be ignited by percussion and, additionally, an electric bridge primer, are preferably inserted in threaded primers for ammunition of a larger caliber. However, this combination, in its present design, is unsuitable for automatic firearms, since it is not sufficiently shockproof.

The above-mentioned conventional electric priming means contain a perforated metallic shell and a pole piece disposed to be insulated with respect to this shell. This pole piece is held by a thrust ring, said ring being firmly connected to the shell by flanging. The thrust ring and the pole piece are insulated with respect to each other. Such an arrangement has proved well suitable for electric ignition. However, this arrangement is completely unsatisfactory for percussion priming. In this situation the firing pin strikes the pole piece inwardly, in which case gas can escape toward the rear between the shell and the pole piece. Since, in the interest of stability (ruggedness), the pole piece must be fashioned to be very thick, the percussion sensitivity of the primer means is reduced in an undesirable manner.

Although the disadvantage of gas escaping at the bottom does not occur in a primer suitable only for percussion priming, such primer cannot be employed for electric ignition, since the necessary current supply using two lead (feeder) electrodes is impossible in such a construction.

SUMMARY OF THE INVENTION An object of the present invention is to avoid the prior art disadvantages in providing a primer for electric and percussion fuses for cartridge ammunition.

Another object of the present invention is to provide a primer for electric and percussion priming suitable for infantry cartridge caliber up to cartridge ammunition for automatic firearms of a larger caliber, and being constructed in such a manner that safety is ensured up to an acceleration of 500,000 gs.

A further object of the present invention is to provide a primer for both electric and percussion priming which eliminates flashing and is sufficiently shockproof to make it suitable for automatic fire-arms.

Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

Pursuant to the present invention it has been found that the above-mentioned disadvantages may be eliminated and an improved primer for electric and percussion fuses for cartridge ammunition may be obtained by providing that the case of the primer is composed of a metallic capsule with a closed bottom, as the lead electrode to a gap (high-tension) charge, and that there is arranged in the interior of the primer a thrust ring, completely insulated with respect to the capsule, as the second lead electrode for the gap charge and as the current connection'to the propellant charge case (cartridge). The thrust ring is held by a flange of the capsule resting on an insulating ring. As the abutment for the percussion priming means, an anvil is arranged in the thrust ring. This anvil can either be joined to the thrust ring by solid flanging, or can be threadedly inserted therein by means of a thread.

DESCRIPTION OF THE DRAWINGS The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only and thus are not limitative of the present invention and wherein,

FIG. 1 shows a sectional view of a conventional primer;

FIG. 2 shows the effects on the primer of FIG. 1 after a percussion priming (detonation);

FIG. 3 shows a sectional view of the primer of the present invention;

FIG. 4 shows a sectional view of a primer inserted in the propellant charge case;

FIG. 5 shows the disposition of the anvil in the thrust ring by means of a flange; and

. FIG. 6 shows the mounting of the anvil in the thrust ring by means of a thread.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The conventional priming element in FIG. 1 exhibits a metallic shell 1 provided with a bore and a pole piece 3 arranged to be insulated with respect to this shell by means of an insulating cup 2. This pole piece is held by a thrust ring 4 firmly connected to the shell 1 by a flange 5. The thrust ring 4 and the pole piece 3 are likewise insulated from each other by means of a disk 6. The thickness of the disk 6 provides the gap required for the electric ignition. The primer charge 7 is provided in this system in compressed form and is protected by means of a lid varnished on the outside.

In FIG. 2, the disadvantages of this electric high-tension (spark gap) primer are demonstrated. When igniting the primer charge 7 by means of a striker pin 8, the pole piece 3 is pressed toward the inside, and the insulating cup 2, as well as the disk 6 are deformed by squeezing.

The gases produced by the ignition of the primer.

case of all firearms, especially in the case of automaticfirearms, since it leads to flashing and thus to undesirable disturbances. Such flashing particularly occurs on the tip of the firing pin and on the surface of the plate through which the tip of the firing pin extends.

In constrast thereto, the primer according to the present invention is fashioned so that a thrust ring is disposed in a metallic capsule 9, said ring being insulated with respect to the capsule, that is, with respect to the bottom thereof, by means of an insulating ring 11, with respect to the sidewall by means of cylindrical insulation 12, and with respect to the flange 13 by means of an insulating ring 14. By means of the flange 13, the capsule is fixedly connected with the thrust ring, the flange resting on the insulating ring 14. The capsule 9 and the thrust ring 10 represent the two lead (feeder) electrodes to a gap charge 15. A primer charge 16 is disposed on the gap charge by pressing. This primer charge is provided with a hemispherical (cap-shaped) element into which the anvil 17 extends. The primer charge proper is covered with a foil 18 of metal or paper.

The electrically conductive gap charge 15 consists predominantly of lead trinitroresorcinate or a similar inflammable (ignitable) component, containing as the electrically conductive means an effective amount of graphite or carbon black. In order to obtain percussion sensitivity, a proportion of about 2-2 percent of tetrazene as well as a friction agent, consisting of powdered glass or calcium silicide or antimony sulfide, are admixed to the charge.

The primer charge 16 contains a pyrotechnical mixture required for igniting the powder. It can comprise for example, a mixture of lead dioxide, calcium silicide, and barium nitrate. However, it is also possible to select the electric and percussion-sensitive charge 16 with respect to its composition in such a manner that it is already able to ignite a propellant.

According to FIG. 4, the anvil 17 and the thrust ring 10 together are disposed in the inside bottom of the propellant charge case 19. With respect to the body of the case 19, the capsule 9 is electrically separated by an insulation 20.

In case of an ignition by percussion, the bottom of the capsule 9 is bent toward the anvil 17, and the interposed gap charge 15 is ignited. The flash of the gap charge 15 and the primer charge 16 escapes through the apertures 21 of the anvil 17 into the flash hole 22.

In case of an electric ignition, current is fed to the capsule 9 and the case 19. The capsule forms the positive pole, and the case forms the negative pole. The cap charge 15 is ignited across the gap formed by the insulating ring 11 between the bottom of the capsule and the thrust ring 10, by the current flowing from the capsule 9 through the gap charge 15 into the thrust ring 10. The latter is in contact with the anvil 17 and the case 19. The electrically conductive gap charge 15 ignites the primer charge 16. The gases escaping through the apertures 21 of the anvil 17 and through the flash hole 22 of the case 19 ignites the powder contained in the case.

FIGS. 5 and 6 show two ways of mounting the anvil 17 in the thrust ring 10, in the first instance by means of a flange 23 and in the second instance by means of a thread 24.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be apparent to one skilled in the art are intended to be included.

We claim:

1. A primer for electric and percussion priming for use in accordance with the spark-gap principle which comprises a metallic capsule provided with a closed bottom, an electrically conductive thrust ring disposed inside of the metallic capsule, insulating means for completely insulating the thrust ring from the metallic capsule, and a gap charge provided inside the thrust ring and adjacent the closed bottom of the metallic capsule, the metallic capsule and the thrust ring being arranged for connection with electrical means such that the metallic capsule acts as a first lead electrode to the gap charge and the thrust ring acts as a second lead electrode for the gap charge.

2. The primer of claim 1, wherein the metallic capsule is provided with a flange which holds the thrust ring inside said capsule, said flange and said thrust means being separated by insulating means.

3. The primer of claim 2, wherein a primer charge is provided adjacent the gap charge and an anvil is disposed inside the thrust ring as an abutment for the percussion priming means.

4. The primer of claim 3, wherein the anvil is connected with the thrust ring by flange means.

5. The primer of claim 3, wherein the anvil is screwed into the thrust ring by means of a thread means.

6. The primer of claim 1, further comprising a metallic propellant charge case containing a propellant charge and having said metallic capsule disposed therein, further insulating means for insulating said metallic capsule from the metallic case, and said thrust ring providing the electrical connection to the propellant charge case.

7. A primer for electric and percussion priming for use in accordance with the spark-gap principle which comprises a shell-like metallic capsule provided with a closed bottom and a flanged open end, an electrically conductive thrust ring annularly disposed inside of the metallic capsule and adapted to be held in position by said flanged portions, insulating means for completely insulating said thrust ring from the bottom, sidewalls and flange portion of the metallic capsule, a gap charge provided inside the thrust ring and adjacent the closed bottom of the metallic capsule, a primer charge provided inside the thrust ring and adjacent the gap charge and an anvil disposed inside the thrust ring as an abutment for the percussion priming means, said metallic capsule and said thrust ring being arranged for connection with electrical means such that said metallic capsule and said thrust ring serve as the two lead electrodes to the gap charge.

8. The primer of claim 7, wherein the primer charge is provided with a hemispherical element into which the anvil extends.

9. The primer of claim 8, wherein the primer charge is provided with a metal or paper cover.

10. The primer of claim 7, wherein the gap charge contains lead trinitroresorcinate containing as an electrically conductive means an effective amount of graphite or carbon black.

1 l. The primer of claim 10, wherein said gap charge further contains about 2 to 3 percent tetrazene, and a friction agent selected from the group consisting of powdered glass, calcium silicide or antimony sulfide.

and said thrust ring providing the electrical connection to the propellant charge case.

14. The primer of claim 7, wherein the anvil is connected with the thrust ring by a flange means.

15. The primer of claim 7, wherein the anvil is screwed into the thrust ring by means of a thread means. 

1. A primer for electric and percussion priming for use in accordance with the spark-gap principle which comprises a metallic capsule provided with a closed bottom, an electrically conductive thrust ring disposed inside of the metallic capsule, insulating means for completely insulating the thrust ring from the metallic capsule, and a gap charge provided inside the thrust ring and adjacent the closed bottom of the metallic capsule, the metallic capsule and the thrust ring being arranged for connection with electrical means such that the metallic capsule acts as a first lead electrode to the gap charge and the thrust ring acts as a second lead electrode for the gap charge.
 2. The primer of claim 1, wherein the metallic capsule is provided with a flange which holds the thrust ring inside said capsule, said flange and said thrust means being separated by insulating means.
 3. The primer of claim 2, wherein a primer charge is provided adjacent the gap charge and an anvil is disposed inside the thrust ring as an abutment for the percussion priming means.
 4. The primer of claim 3, wherein the anvil is connected with the thrust ring by flange means.
 5. The primer of claim 3, wherein the anvil is screwed into the thrust ring by means of a thread means.
 6. The primer of claim 1, further comprising a metallic propellant charge case containing a propellant charge and having said metallic capsule disposed therein, further insulating means for insulating said metallic capsule from the metallic case, and said thrust ring providing the electrical connection to the propellant charge case.
 7. A primer for electric and percussion priming for use in accordance with the spark-gap principle which comprises a shell-like metallic capsule provided with a closed bottom and a flanged open end, an electrically conductive thrust ring annularly disposed inside of the metallic capsule and adapted to be held in position by said flanged portions, insulating means for completely insulating said thrust ring from the bottom, sidewalls and flange portion of the metallic capsule, a gap charge provided inside the thrust ring and adjacent the closed bottom of the metallic capsule, a primer charge provided inside the thrust ring and adjacent the gap charge and an anvil disposed inside the thrust ring as an abutment for the percussion priming means, said metallic capsule and said thrust ring being arranged for connection with electrical means such that said metallic capsule and said thrust ring serve as the two lead electrodes to the gap charge.
 8. The primer of claim 7, wherein the primer charge is provided with a hemispherical element into which the anvil extends.
 9. The primer of claim 8, wherein the primer charge is provided with a metal or paper cover.
 10. The primer of claim 7, wherein the gap charge contains lead trinitroresorcinate containing as an electrically conductive means an effective amount of graphite or carbon black.
 11. The primer of claim 10, wherein said gap charge further contains about 2 to 3 percent tetrazene, and a friction agent selected from the group consisting of powdered glass, calcium silicide or antimony sulfide.
 12. The primer of claim 11, wherein the primer charge contains a mixture of lead dioxide, calcium silicide and barium nitrate.
 13. The primer of claim 7, further comprising a metallic propellant charge case containing a propellant charge and having said metallic capsule disposed therein, further insulating means for electrically separating said metallic capsule from the metallic case, and said thrust ring providing the electrical connection to the propellant charge case.
 14. The primer of claim 7, wherein the anvil is connected with the thrust ring by a flange means. 